Epigenomics is developing a colon cancer screening assay based on differential methylation of specific CpG sites for the detection of early stage disease. A genome-wide methylation analysis and oligonucleotide array study using DNA from various stages of colon cancer and normal tissue have been completed to obtain candidate CpG markers. Based on results obtained in the above studies, Epigenomics has moved to the final stages of feasibility with a specific, highly sensitive real-time marker assay that is able to detect colon cancer DNA in blood plasma.

From public health as well as health economics perspectives, the poor adoption of current screening options limits the effectiveness of CRC screening initiatives; as stated by Sidney Winawer, MD, "the best test is the one that gets done." Current CRC screening guidelines include FOBT, sigmoidoscopy (alone or with FOBT), or colonoscopy. Non-invasive screening is conducted using FOBT, which while inexpensive, exhibits a low compliance rate (around 16% in the US) due to its use restrictions, perceived inconvenience and lack of consumer acceptance. The gold standard procedure for CRC detection is colonoscopy; it exhibits excellent performance characteristics, but has a limited utility as a first line screen due to its high cost, healthcare delivery resource limitations, and inadequate patient acceptance. It is believed a noninvasive, first-line screening assay capable of detecting individuals with colorectal disease, confirmed by colonoscopy, would have greater utility for population screening.

Epigenomics has identified methylated gene regions that are specific for colorectal cancer or pre-malignant tissue. Aberrantly methylated genes represent attractive candidate markers for cancer screening, as cancer-specific methylation changes occur early in tumorigenesis, appear to be stable, yield a positive amplifiable signal, and can be assayed with high analytical sensitivity. Since methylation occurs early and in distinct genomic areas, it is possible to achieve high clinical sensitivity with a small number of methylated DNA markers. Studies have shown that aberrantly methylated DNA markers can be detected in tissue and body fluids and are highly correlated to colorectal cancer.

Inclusion Criteria:

• Group 1 diagnosis of colorectal cancer

Exclusion Criteria:

• Group 2 diagnosis of colorectal cancer

Subjects are identified at colonoscopy as having or not having colorectal cancer. Blood from all subjects was drawn either before or more than 2 days and up to 6 months after colonoscopy and prior to starting any cancer specific treatment. Cancer diagnosis was confirmed histologically from the surgical specimen and only adenocarcinomas were included in this study.